I agree with WIChix. I did notice that the 66 was a back clamp and I couldn't tell for sure about the attachments in the drawer. Usually, one only uses the regular presser foot, but sometimes a special attachment comes in handy.
I'm glad you checked with Sandman's as it is indeed a 66 as that was the only machine with those decals.
I see you happened across one of the mistakes in the Singer serial number database. "G" numbers are tricky, partially when someone leaves out a number when looking it up or not looking far enough as the "G" numbers start over with a "0" in front of them.
Janey - Neat people never make the exciting discoveries I do.